What Is Content Security Policy (CSP) in Magento, and Why Does It Matter?

Table of Contents

• What Is Content Security Policy in Magento?
• How CSP Works in Magento
• Report-only vs Restrict Mode
• Changes in Magento 2.4.7+
• What “Restrict Mode Required” Really Means
• Magento Open Source vs Adobe Commerce Cloud
• Key CSP Directives for eCommerce
• Inline Scripts, Hashes, and Nonces
• A Safe Rollout Approach
• FAQ

What Is Content Security Policy (CSP) in Magento, and Why It Matters

Content Security Policy is a browser-enforced security layer that limits which scripts and resources a page can load and execute. Instead of trusting any code that reaches the browser, CSP defines clear rules for what is allowed. Adobe Commerce includes CSP to reduce risks such as cross-site scripting and client-side injection attacks.

CSP has become increasingly important as PCI DSS 4.0 compliance expectations raise the standards for client-side script control on checkout. This article explains how CSP works in Magento, the difference between report-only and restrict mode, what changed in 2.4.7+, and how to roll out CSP without disrupting checkout.

How CSP Works in Magento

Magento’s CSP implementation is more than a single header. It includes a structured policy system across storefront and Admin, with configurable allow-lists for common directives.

CSP started in report-only mode by default in Magento version 2.3.5. This setting logs policy violations but does not block code execution. When teams review these logs, report-only mode provides a safe way to discover everything the site depends on.

Restrict mode is the enforcement layer. The browser blocks behavior that does not match the policy, which often reveals scripts and inline logic that were never documented.

Report-only vs Restrict Mode, and Why Rollout Matters

Report-only mode is a discovery tool. It helps teams identify the scripts, endpoints, and inline behaviors that both storefront and checkout rely on. It is the safest first step, but only works when violation logs are reviewed consistently.

Restrict mode enforces the policy. When a script or resource does not meet the rules, the browser stops it. This is where checkout issues, missing UI behaviors, or third-party failures become visible. Magento supports phased rollout because this transition can expose long-standing, undocumented dependencies.

What Changed in Magento 2.4.7+ (And Why Checkout Is Affected First)

Adobe Commerce and Magento Open Source 2.4.7+ introduced a significant shift:

• Payment pages in storefront and Admin run in restrict mode by default.
• All other pages remain in report-only mode unless changed manually.

This is not global enforcement. Magento enforces CSP where risk is highest. Checkout interactions rely on inline JavaScript, dynamically loaded resources, and third-party scripts, and enforcement often exposes hidden dependencies.

What "Restrict Mode Is Required on 2.4.7+" Actually Means

It is more accurate to say that Magento 2.4.7+ uses default enforcement on payment pages. Other pages stay in report-only mode unless developers change the configuration. Restrict mode is not globally required, but checkout must meet these stricter standards.

Magento Open Source vs Adobe Commerce Cloud: CSP Differences

The feature set and default behavior are the same across Magento Open Source and Adobe Commerce in 2.4.7+.

Differences mostly relate to operational workflows:

• deployment and configuration processes
• caching and CDN behavior
• environment management patterns

These factors can change how CSP is tested and rolled out, but they do not alter how CSP itself works.

The Directives That Matter Most for eCommerce

Teams often focus on script-src because script blocking is obvious. But several other directives affect Magento storefront behavior:

• connect-src for API calls, analytics, and vendor endpoints
• frame-src for iframes and hosted payment solutions
• img-src for tracking pixels and dynamic images

A common pattern is when a script loads but does not function. In strict CSP environments, this typically indicates a missing connect-src or frame-src permission.

Inline Scripts: Hashes, Nonces, and Practical Considerations

Inline JavaScript becomes a challenge when restrict mode is enabled, especially on payment pages. Inline execution is blocked unless explicitly allowed.

Magento supports two mechanisms:

• Hash allowlisting for stable inline blocks
• Nonce-based execution using a CSP nonce provider introduced in 2.4.7+

Many legacy themes contain inline scripts in templates. These become immediate blockers under enforcement. Most teams reduce inline scripts, allowlist only stable inline blocks, and use nonces carefully, especially when caching is involved.

A Safe Rollout Approach

The following version-aware rollout approach works consistently across Magento storefronts and supports smoother PCI compliance and platform governance:

1. Run report-only mode broadly and review violation logs.
2. Separate checkout-critical scripts from UX or marketing enhancements.
3. Tighten allowlists by directive: script, connect, img, frame.
4. Enable restrict mode on payment pages and perform full checkout regression testing.
5. Monitor CSP reports and adjust as integrations and vendors evolve.

Avoid broad wildcards such as * in allowlists. They weaken control and can create PCI audit complications.

FAQ: CSP in Magento

• What is CSP, in plain terms?

  CSP is a browser-enforced rule set that limits which scripts and resources a page can load. Magento uses it to reduce client-side injection risks.

• What is the difference between report-only and restrict mode?

  Report-only logs violations without blocking anything. Restrict mode enforces the policy and blocks non-compliant code. Report-only is the safest place to begin.

• Is restrict mode enabled by default in Magento 2.4.7+?

  Yes, but only for payment pages. All other pages remain in report-only mode unless updated manually.

• Are there CSP differences between Magento Open Source and Adobe Commerce Cloud?

  No differences in core features or defaults. Operational workflows can influence how CSP is tested and deployed, but the policy behavior is the same.

• Why do CSP issues appear in checkout first?

  Checkout is the only area with default enforcement, and it relies heavily on inline scripts and third-party resources. This makes CSP conflicts more visible there.

• What matters most when enforcing CSP on payment pages?

  Checkout testing is essential. Validate guest and logged-in flows, shipping and tax updates, all payment methods including 3DS, mobile checkout, and success page behavior.